1/*
2 * Builtin "git merge"
3 *
4 * Copyright (c) 2008 Miklos Vajna <vmiklos@frugalware.org>
5 *
6 * Based on git-merge.sh by Junio C Hamano.
7 */
8#include "cache.h"
10#include "parse-options.h"
11#include "builtin.h"
12#include "lockfile.h"
13#include "run-command.h"
14#include "diff.h"
15#include "refs.h"
16#include "commit.h"
17#include "diffcore.h"
18#include "revision.h"
19#include "unpack-trees.h"
20#include "cache-tree.h"
21#include "dir.h"
22#include "utf8.h"
23#include "log-tree.h"
24#include "color.h"
25#include "rerere.h"
26#include "help.h"
27#include "merge-recursive.h"
28#include "resolve-undo.h"
29#include "remote.h"
30#include "fmt-merge-msg.h"
31#include "gpg-interface.h"
32#include "sequencer.h"
33#define DEFAULT_TWOHEAD (1<<0)
35#define DEFAULT_OCTOPUS (1<<1)
36#define NO_FAST_FORWARD (1<<2)
37#define NO_TRIVIAL (1<<3)
38struct strategy {
40 const char *name;
41 unsigned attr;
42};
43static const char * const builtin_merge_usage[] = {
45 N_("git merge [<options>] [<commit>...]"),
46 N_("git merge [<options>] <msg> HEAD <commit>"),
47 N_("git merge --abort"),
48 NULL
49};
50static int show_diffstat = 1, shortlog_len = -1, squash;
52static int option_commit = 1;
53static int option_edit = -1;
54static int allow_trivial = 1, have_message, verify_signatures;
55static int overwrite_ignore = 1;
56static struct strbuf merge_msg = STRBUF_INIT;
57static struct strategy **use_strategies;
58static size_t use_strategies_nr, use_strategies_alloc;
59static const char **xopts;
60static size_t xopts_nr, xopts_alloc;
61static const char *branch;
62static char *branch_mergeoptions;
63static int option_renormalize;
64static int verbosity;
65static int allow_rerere_auto;
66static int abort_current_merge;
67static int allow_unrelated_histories;
68static int show_progress = -1;
69static int default_to_upstream = 1;
70static const char *sign_commit;
71static struct strategy all_strategy[] = {
73 { "recursive", DEFAULT_TWOHEAD | NO_TRIVIAL },
74 { "octopus", DEFAULT_OCTOPUS },
75 { "resolve", 0 },
76 { "ours", NO_FAST_FORWARD | NO_TRIVIAL },
77 { "subtree", NO_FAST_FORWARD | NO_TRIVIAL },
78};
79static const char *pull_twohead, *pull_octopus;
81enum ff_type {
83 FF_NO,
84 FF_ALLOW,
85 FF_ONLY
86};
87static enum ff_type fast_forward = FF_ALLOW;
89static int option_parse_message(const struct option *opt,
91 const char *arg, int unset)
92{
93 struct strbuf *buf = opt->value;
94 if (unset)
96 strbuf_setlen(buf, 0);
97 else if (arg) {
98 strbuf_addf(buf, "%s%s", buf->len ? "\n\n" : "", arg);
99 have_message = 1;
100 } else
101 return error(_("switch `m' requires a value"));
102 return 0;
103}
104static struct strategy *get_strategy(const char *name)
106{
107 int i;
108 struct strategy *ret;
109 static struct cmdnames main_cmds, other_cmds;
110 static int loaded;
111 if (!name)
113 return NULL;
114 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
116 if (!strcmp(name, all_strategy[i].name))
117 return &all_strategy[i];
118 if (!loaded) {
120 struct cmdnames not_strategies;
121 loaded = 1;
122 memset(¬_strategies, 0, sizeof(struct cmdnames));
124 load_command_list("git-merge-", &main_cmds, &other_cmds);
125 for (i = 0; i < main_cmds.cnt; i++) {
126 int j, found = 0;
127 struct cmdname *ent = main_cmds.names[i];
128 for (j = 0; j < ARRAY_SIZE(all_strategy); j++)
129 if (!strncmp(ent->name, all_strategy[j].name, ent->len)
130 && !all_strategy[j].name[ent->len])
131 found = 1;
132 if (!found)
133 add_cmdname(¬_strategies, ent->name, ent->len);
134 }
135 exclude_cmds(&main_cmds, ¬_strategies);
136 }
137 if (!is_in_cmdlist(&main_cmds, name) && !is_in_cmdlist(&other_cmds, name)) {
138 fprintf(stderr, _("Could not find merge strategy '%s'.\n"), name);
139 fprintf(stderr, _("Available strategies are:"));
140 for (i = 0; i < main_cmds.cnt; i++)
141 fprintf(stderr, " %s", main_cmds.names[i]->name);
142 fprintf(stderr, ".\n");
143 if (other_cmds.cnt) {
144 fprintf(stderr, _("Available custom strategies are:"));
145 for (i = 0; i < other_cmds.cnt; i++)
146 fprintf(stderr, " %s", other_cmds.names[i]->name);
147 fprintf(stderr, ".\n");
148 }
149 exit(1);
150 }
151 ret = xcalloc(1, sizeof(struct strategy));
153 ret->name = xstrdup(name);
154 ret->attr = NO_TRIVIAL;
155 return ret;
156}
157static void append_strategy(struct strategy *s)
159{
160 ALLOC_GROW(use_strategies, use_strategies_nr + 1, use_strategies_alloc);
161 use_strategies[use_strategies_nr++] = s;
162}
163static int option_parse_strategy(const struct option *opt,
165 const char *name, int unset)
166{
167 if (unset)
168 return 0;
169 append_strategy(get_strategy(name));
171 return 0;
172}
173static int option_parse_x(const struct option *opt,
175 const char *arg, int unset)
176{
177 if (unset)
178 return 0;
179 ALLOC_GROW(xopts, xopts_nr + 1, xopts_alloc);
181 xopts[xopts_nr++] = xstrdup(arg);
182 return 0;
183}
184static int option_parse_n(const struct option *opt,
186 const char *arg, int unset)
187{
188 show_diffstat = unset;
189 return 0;
190}
191static struct option builtin_merge_options[] = {
193 { OPTION_CALLBACK, 'n', NULL, NULL, NULL,
194 N_("do not show a diffstat at the end of the merge"),
195 PARSE_OPT_NOARG, option_parse_n },
196 OPT_BOOL(0, "stat", &show_diffstat,
197 N_("show a diffstat at the end of the merge")),
198 OPT_BOOL(0, "summary", &show_diffstat, N_("(synonym to --stat)")),
199 { OPTION_INTEGER, 0, "log", &shortlog_len, N_("n"),
200 N_("add (at most <n>) entries from shortlog to merge commit message"),
201 PARSE_OPT_OPTARG, NULL, DEFAULT_MERGE_LOG_LEN },
202 OPT_BOOL(0, "squash", &squash,
203 N_("create a single commit instead of doing a merge")),
204 OPT_BOOL(0, "commit", &option_commit,
205 N_("perform a commit if the merge succeeds (default)")),
206 OPT_BOOL('e', "edit", &option_edit,
207 N_("edit message before committing")),
208 OPT_SET_INT(0, "ff", &fast_forward, N_("allow fast-forward (default)"), FF_ALLOW),
209 { OPTION_SET_INT, 0, "ff-only", &fast_forward, NULL,
210 N_("abort if fast-forward is not possible"),
211 PARSE_OPT_NOARG | PARSE_OPT_NONEG, NULL, FF_ONLY },
212 OPT_RERERE_AUTOUPDATE(&allow_rerere_auto),
213 OPT_BOOL(0, "verify-signatures", &verify_signatures,
214 N_("verify that the named commit has a valid GPG signature")),
215 OPT_CALLBACK('s', "strategy", &use_strategies, N_("strategy"),
216 N_("merge strategy to use"), option_parse_strategy),
217 OPT_CALLBACK('X', "strategy-option", &xopts, N_("option=value"),
218 N_("option for selected merge strategy"), option_parse_x),
219 OPT_CALLBACK('m', "message", &merge_msg, N_("message"),
220 N_("merge commit message (for a non-fast-forward merge)"),
221 option_parse_message),
222 OPT__VERBOSITY(&verbosity),
223 OPT_BOOL(0, "abort", &abort_current_merge,
224 N_("abort the current in-progress merge")),
225 OPT_BOOL(0, "allow-unrelated-histories", &allow_unrelated_histories,
226 N_("allow merging unrelated histories")),
227 OPT_SET_INT(0, "progress", &show_progress, N_("force progress reporting"), 1),
228 { OPTION_STRING, 'S', "gpg-sign", &sign_commit, N_("key-id"),
229 N_("GPG sign commit"), PARSE_OPT_OPTARG, NULL, (intptr_t) "" },
230 OPT_BOOL(0, "overwrite-ignore", &overwrite_ignore, N_("update ignored files (default)")),
231 OPT_END()
232};
233/* Cleans up metadata that is uninteresting after a succeeded merge. */
235static void drop_save(void)
236{
237 unlink(git_path_merge_head());
238 unlink(git_path_merge_msg());
239 unlink(git_path_merge_mode());
240}
241static int save_state(unsigned char *stash)
243{
244 int len;
245 struct child_process cp = CHILD_PROCESS_INIT;
246 struct strbuf buffer = STRBUF_INIT;
247 const char *argv[] = {"stash", "create", NULL};
248 cp.argv = argv;
250 cp.out = -1;
251 cp.git_cmd = 1;
252 if (start_command(&cp))
254 die(_("could not run stash."));
255 len = strbuf_read(&buffer, cp.out, 1024);
256 close(cp.out);
257 if (finish_command(&cp) || len < 0)
259 die(_("stash failed"));
260 else if (!len) /* no changes */
261 return -1;
262 strbuf_setlen(&buffer, buffer.len-1);
263 if (get_sha1(buffer.buf, stash))
264 die(_("not a valid object: %s"), buffer.buf);
265 return 0;
266}
267static void read_empty(unsigned const char *sha1, int verbose)
269{
270 int i = 0;
271 const char *args[7];
272 args[i++] = "read-tree";
274 if (verbose)
275 args[i++] = "-v";
276 args[i++] = "-m";
277 args[i++] = "-u";
278 args[i++] = EMPTY_TREE_SHA1_HEX;
279 args[i++] = sha1_to_hex(sha1);
280 args[i] = NULL;
281 if (run_command_v_opt(args, RUN_GIT_CMD))
283 die(_("read-tree failed"));
284}
285static void reset_hard(unsigned const char *sha1, int verbose)
287{
288 int i = 0;
289 const char *args[6];
290 args[i++] = "read-tree";
292 if (verbose)
293 args[i++] = "-v";
294 args[i++] = "--reset";
295 args[i++] = "-u";
296 args[i++] = sha1_to_hex(sha1);
297 args[i] = NULL;
298 if (run_command_v_opt(args, RUN_GIT_CMD))
300 die(_("read-tree failed"));
301}
302static void restore_state(const unsigned char *head,
304 const unsigned char *stash)
305{
306 struct strbuf sb = STRBUF_INIT;
307 const char *args[] = { "stash", "apply", NULL, NULL };
308 if (is_null_sha1(stash))
310 return;
311 reset_hard(head, 1);
313 args[2] = sha1_to_hex(stash);
315 /*
317 * It is OK to ignore error here, for example when there was
318 * nothing to restore.
319 */
320 run_command_v_opt(args, RUN_GIT_CMD);
321 strbuf_release(&sb);
323 refresh_cache(REFRESH_QUIET);
324}
325/* This is called when no merge was necessary. */
327static void finish_up_to_date(const char *msg)
328{
329 if (verbosity >= 0)
330 printf("%s%s\n", squash ? _(" (nothing to squash)") : "", msg);
331 drop_save();
332}
333static void squash_message(struct commit *commit, struct commit_list *remoteheads)
335{
336 struct rev_info rev;
337 struct strbuf out = STRBUF_INIT;
338 struct commit_list *j;
339 struct pretty_print_context ctx = {0};
340 printf(_("Squash commit -- not updating HEAD\n"));
342 init_revisions(&rev, NULL);
344 rev.ignore_merges = 1;
345 rev.commit_format = CMIT_FMT_MEDIUM;
346 commit->object.flags |= UNINTERESTING;
348 add_pending_object(&rev, &commit->object, NULL);
349 for (j = remoteheads; j; j = j->next)
351 add_pending_object(&rev, &j->item->object, NULL);
352 setup_revisions(0, NULL, &rev, NULL);
354 if (prepare_revision_walk(&rev))
355 die(_("revision walk setup failed"));
356 ctx.abbrev = rev.abbrev;
358 ctx.date_mode = rev.date_mode;
359 ctx.fmt = rev.commit_format;
360 strbuf_addstr(&out, "Squashed commit of the following:\n");
362 while ((commit = get_revision(&rev)) != NULL) {
363 strbuf_addch(&out, '\n');
364 strbuf_addf(&out, "commit %s\n",
365 oid_to_hex(&commit->object.oid));
366 pretty_print_commit(&ctx, commit, &out);
367 }
368 write_file_buf(git_path_squash_msg(), out.buf, out.len);
369 strbuf_release(&out);
370}
371static void finish(struct commit *head_commit,
373 struct commit_list *remoteheads,
374 const unsigned char *new_head, const char *msg)
375{
376 struct strbuf reflog_message = STRBUF_INIT;
377 const unsigned char *head = head_commit->object.oid.hash;
378 if (!msg)
380 strbuf_addstr(&reflog_message, getenv("GIT_REFLOG_ACTION"));
381 else {
382 if (verbosity >= 0)
383 printf("%s\n", msg);
384 strbuf_addf(&reflog_message, "%s: %s",
385 getenv("GIT_REFLOG_ACTION"), msg);
386 }
387 if (squash) {
388 squash_message(head_commit, remoteheads);
389 } else {
390 if (verbosity >= 0 && !merge_msg.len)
391 printf(_("No merge message -- not updating HEAD\n"));
392 else {
393 const char *argv_gc_auto[] = { "gc", "--auto", NULL };
394 update_ref(reflog_message.buf, "HEAD",
395 new_head, head, 0,
396 UPDATE_REFS_DIE_ON_ERR);
397 /*
398 * We ignore errors in 'gc --auto', since the
399 * user should see them.
400 */
401 close_all_packs();
402 run_command_v_opt(argv_gc_auto, RUN_GIT_CMD);
403 }
404 }
405 if (new_head && show_diffstat) {
406 struct diff_options opts;
407 diff_setup(&opts);
408 opts.stat_width = -1; /* use full terminal width */
409 opts.stat_graph_width = -1; /* respect statGraphWidth config */
410 opts.output_format |=
411 DIFF_FORMAT_SUMMARY | DIFF_FORMAT_DIFFSTAT;
412 opts.detect_rename = DIFF_DETECT_RENAME;
413 diff_setup_done(&opts);
414 diff_tree_sha1(head, new_head, "", &opts);
415 diffcore_std(&opts);
416 diff_flush(&opts);
417 }
418 /* Run a post-merge hook */
420 run_hook_le(NULL, "post-merge", squash ? "1" : "0", NULL);
421 strbuf_release(&reflog_message);
423}
424/* Get the name for the merge commit's message. */
426static void merge_name(const char *remote, struct strbuf *msg)
427{
428 struct commit *remote_head;
429 unsigned char branch_head[20];
430 struct strbuf buf = STRBUF_INIT;
431 struct strbuf bname = STRBUF_INIT;
432 const char *ptr;
433 char *found_ref;
434 int len, early;
435 strbuf_branchname(&bname, remote);
437 remote = bname.buf;
438 memset(branch_head, 0, sizeof(branch_head));
440 remote_head = get_merge_parent(remote);
441 if (!remote_head)
442 die(_("'%s' does not point to a commit"), remote);
443 if (dwim_ref(remote, strlen(remote), branch_head, &found_ref) > 0) {
445 if (starts_with(found_ref, "refs/heads/")) {
446 strbuf_addf(msg, "%s\t\tbranch '%s' of .\n",
447 sha1_to_hex(branch_head), remote);
448 goto cleanup;
449 }
450 if (starts_with(found_ref, "refs/tags/")) {
451 strbuf_addf(msg, "%s\t\ttag '%s' of .\n",
452 sha1_to_hex(branch_head), remote);
453 goto cleanup;
454 }
455 if (starts_with(found_ref, "refs/remotes/")) {
456 strbuf_addf(msg, "%s\t\tremote-tracking branch '%s' of .\n",
457 sha1_to_hex(branch_head), remote);
458 goto cleanup;
459 }
460 }
461 /* See if remote matches <name>^^^.. or <name>~<number> */
463 for (len = 0, ptr = remote + strlen(remote);
464 remote < ptr && ptr[-1] == '^';
465 ptr--)
466 len++;
467 if (len)
468 early = 1;
469 else {
470 early = 0;
471 ptr = strrchr(remote, '~');
472 if (ptr) {
473 int seen_nonzero = 0;
474 len++; /* count ~ */
476 while (*++ptr && isdigit(*ptr)) {
477 seen_nonzero |= (*ptr != '0');
478 len++;
479 }
480 if (*ptr)
481 len = 0; /* not ...~<number> */
482 else if (seen_nonzero)
483 early = 1;
484 else if (len == 1)
485 early = 1; /* "name~" is "name~1"! */
486 }
487 }
488 if (len) {
489 struct strbuf truname = STRBUF_INIT;
490 strbuf_addf(&truname, "refs/heads/%s", remote);
491 strbuf_setlen(&truname, truname.len - len);
492 if (ref_exists(truname.buf)) {
493 strbuf_addf(msg,
494 "%s\t\tbranch '%s'%s of .\n",
495 oid_to_hex(&remote_head->object.oid),
496 truname.buf + 11,
497 (early ? " (early part)" : ""));
498 strbuf_release(&truname);
499 goto cleanup;
500 }
501 strbuf_release(&truname);
502 }
503 if (remote_head->util) {
505 struct merge_remote_desc *desc;
506 desc = merge_remote_util(remote_head);
507 if (desc && desc->obj && desc->obj->type == OBJ_TAG) {
508 strbuf_addf(msg, "%s\t\t%s '%s'\n",
509 oid_to_hex(&desc->obj->oid),
510 typename(desc->obj->type),
511 remote);
512 goto cleanup;
513 }
514 }
515 strbuf_addf(msg, "%s\t\tcommit '%s'\n",
517 oid_to_hex(&remote_head->object.oid), remote);
518cleanup:
519 strbuf_release(&buf);
520 strbuf_release(&bname);
521}
522static void parse_branch_merge_options(char *bmo)
524{
525 const char **argv;
526 int argc;
527 if (!bmo)
529 return;
530 argc = split_cmdline(bmo, &argv);
531 if (argc < 0)
532 die(_("Bad branch.%s.mergeoptions string: %s"), branch,
533 split_cmdline_strerror(argc));
534 REALLOC_ARRAY(argv, argc + 2);
535 memmove(argv + 1, argv, sizeof(*argv) * (argc + 1));
536 argc++;
537 argv[0] = "branch.*.mergeoptions";
538 parse_options(argc, argv, NULL, builtin_merge_options,
539 builtin_merge_usage, 0);
540 free(argv);
541}
542static int git_merge_config(const char *k, const char *v, void *cb)
544{
545 int status;
546 if (branch && starts_with(k, "branch.") &&
548 starts_with(k + 7, branch) &&
549 !strcmp(k + 7 + strlen(branch), ".mergeoptions")) {
550 free(branch_mergeoptions);
551 branch_mergeoptions = xstrdup(v);
552 return 0;
553 }
554 if (!strcmp(k, "merge.diffstat") || !strcmp(k, "merge.stat"))
556 show_diffstat = git_config_bool(k, v);
557 else if (!strcmp(k, "pull.twohead"))
558 return git_config_string(&pull_twohead, k, v);
559 else if (!strcmp(k, "pull.octopus"))
560 return git_config_string(&pull_octopus, k, v);
561 else if (!strcmp(k, "merge.renormalize"))
562 option_renormalize = git_config_bool(k, v);
563 else if (!strcmp(k, "merge.ff")) {
564 int boolval = git_config_maybe_bool(k, v);
565 if (0 <= boolval) {
566 fast_forward = boolval ? FF_ALLOW : FF_NO;
567 } else if (v && !strcmp(v, "only")) {
568 fast_forward = FF_ONLY;
569 } /* do not barf on values from future versions of git */
570 return 0;
571 } else if (!strcmp(k, "merge.defaulttoupstream")) {
572 default_to_upstream = git_config_bool(k, v);
573 return 0;
574 } else if (!strcmp(k, "commit.gpgsign")) {
575 sign_commit = git_config_bool(k, v) ? "" : NULL;
576 return 0;
577 }
578 status = fmt_merge_msg_config(k, v, cb);
580 if (status)
581 return status;
582 status = git_gpg_config(k, v, NULL);
583 if (status)
584 return status;
585 return git_diff_ui_config(k, v, cb);
586}
587static int read_tree_trivial(unsigned char *common, unsigned char *head,
589 unsigned char *one)
590{
591 int i, nr_trees = 0;
592 struct tree *trees[MAX_UNPACK_TREES];
593 struct tree_desc t[MAX_UNPACK_TREES];
594 struct unpack_trees_options opts;
595 memset(&opts, 0, sizeof(opts));
597 opts.head_idx = 2;
598 opts.src_index = &the_index;
599 opts.dst_index = &the_index;
600 opts.update = 1;
601 opts.verbose_update = 1;
602 opts.trivial_merges_only = 1;
603 opts.merge = 1;
604 trees[nr_trees] = parse_tree_indirect(common);
605 if (!trees[nr_trees++])
606 return -1;
607 trees[nr_trees] = parse_tree_indirect(head);
608 if (!trees[nr_trees++])
609 return -1;
610 trees[nr_trees] = parse_tree_indirect(one);
611 if (!trees[nr_trees++])
612 return -1;
613 opts.fn = threeway_merge;
614 cache_tree_free(&active_cache_tree);
615 for (i = 0; i < nr_trees; i++) {
616 parse_tree(trees[i]);
617 init_tree_desc(t+i, trees[i]->buffer, trees[i]->size);
618 }
619 if (unpack_trees(nr_trees, t, &opts))
620 return -1;
621 return 0;
622}
623static void write_tree_trivial(unsigned char *sha1)
625{
626 if (write_cache_as_tree(sha1, 0, NULL))
627 die(_("git write-tree failed to write a tree"));
628}
629static int try_merge_strategy(const char *strategy, struct commit_list *common,
631 struct commit_list *remoteheads,
632 struct commit *head, const char *head_arg)
633{
634 static struct lock_file lock;
635 hold_locked_index(&lock, 1);
637 refresh_cache(REFRESH_QUIET);
638 if (active_cache_changed &&
639 write_locked_index(&the_index, &lock, COMMIT_LOCK))
640 return error(_("Unable to write index."));
641 rollback_lock_file(&lock);
642 if (!strcmp(strategy, "recursive") || !strcmp(strategy, "subtree")) {
644 int clean, x;
645 struct commit *result;
646 struct commit_list *reversed = NULL;
647 struct merge_options o;
648 struct commit_list *j;
649 if (remoteheads->next) {
651 error(_("Not handling anything other than two heads merge."));
652 return 2;
653 }
654 init_merge_options(&o);
656 if (!strcmp(strategy, "subtree"))
657 o.subtree_shift = "";
658 o.renormalize = option_renormalize;
660 o.show_rename_progress =
661 show_progress == -1 ? isatty(2) : show_progress;
662 for (x = 0; x < xopts_nr; x++)
664 if (parse_merge_opt(&o, xopts[x]))
665 die(_("Unknown option for merge-recursive: -X%s"), xopts[x]);
666 o.branch1 = head_arg;
668 o.branch2 = merge_remote_util(remoteheads->item)->name;
669 for (j = common; j; j = j->next)
671 commit_list_insert(j->item, &reversed);
672 hold_locked_index(&lock, 1);
674 clean = merge_recursive(&o, head,
675 remoteheads->item, reversed, &result);
676 if (clean < 0)
677 exit(128);
678 if (active_cache_changed &&
679 write_locked_index(&the_index, &lock, COMMIT_LOCK))
680 die (_("unable to write %s"), get_index_file());
681 rollback_lock_file(&lock);
682 return clean ? 0 : 1;
683 } else {
684 return try_merge_command(strategy, xopts_nr, xopts,
685 common, head_arg, remoteheads);
686 }
687}
688static void count_diff_files(struct diff_queue_struct *q,
690 struct diff_options *opt, void *data)
691{
692 int *count = data;
693 (*count) += q->nr;
695}
696static int count_unmerged_entries(void)
698{
699 int i, ret = 0;
700 for (i = 0; i < active_nr; i++)
702 if (ce_stage(active_cache[i]))
703 ret++;
704 return ret;
706}
707static void split_merge_strategies(const char *string, struct strategy **list,
709 int *nr, int *alloc)
710{
711 char *p, *q, *buf;
712 if (!string)
714 return;
715 buf = xstrdup(string);
717 q = buf;
718 for (;;) {
719 p = strchr(q, ' ');
720 if (!p) {
721 ALLOC_GROW(*list, *nr + 1, *alloc);
722 (*list)[(*nr)++].name = xstrdup(q);
723 free(buf);
724 return;
725 } else {
726 *p = '\0';
727 ALLOC_GROW(*list, *nr + 1, *alloc);
728 (*list)[(*nr)++].name = xstrdup(q);
729 q = ++p;
730 }
731 }
732}
733static void add_strategies(const char *string, unsigned attr)
735{
736 struct strategy *list = NULL;
737 int list_alloc = 0, list_nr = 0, i;
738 memset(&list, 0, sizeof(list));
740 split_merge_strategies(string, &list, &list_nr, &list_alloc);
741 if (list) {
742 for (i = 0; i < list_nr; i++)
743 append_strategy(get_strategy(list[i].name));
744 return;
745 }
746 for (i = 0; i < ARRAY_SIZE(all_strategy); i++)
747 if (all_strategy[i].attr & attr)
748 append_strategy(&all_strategy[i]);
749}
751static void read_merge_msg(struct strbuf *msg)
753{
754 const char *filename = git_path_merge_msg();
755 strbuf_reset(msg);
756 if (strbuf_read_file(msg, filename, 0) < 0)
757 die_errno(_("Could not read from '%s'"), filename);
758}
759static void write_merge_state(struct commit_list *);
761static void abort_commit(struct commit_list *remoteheads, const char *err_msg)
762{
763 if (err_msg)
764 error("%s", err_msg);
765 fprintf(stderr,
766 _("Not committing merge; use 'git commit' to complete the merge.\n"));
767 write_merge_state(remoteheads);
768 exit(1);
769}
770static const char merge_editor_comment[] =
772N_("Please enter a commit message to explain why this merge is necessary,\n"
773 "especially if it merges an updated upstream into a topic branch.\n"
774 "\n"
775 "Lines starting with '%c' will be ignored, and an empty message aborts\n"
776 "the commit.\n");
777static void prepare_to_commit(struct commit_list *remoteheads)
779{
780 struct strbuf msg = STRBUF_INIT;
781 strbuf_addbuf(&msg, &merge_msg);
782 strbuf_addch(&msg, '\n');
783 if (0 < option_edit)
784 strbuf_commented_addf(&msg, _(merge_editor_comment), comment_line_char);
785 write_file_buf(git_path_merge_msg(), msg.buf, msg.len);
786 if (run_commit_hook(0 < option_edit, get_index_file(), "prepare-commit-msg",
787 git_path_merge_msg(), "merge", NULL))
788 abort_commit(remoteheads, NULL);
789 if (0 < option_edit) {
790 if (launch_editor(git_path_merge_msg(), NULL, NULL))
791 abort_commit(remoteheads, NULL);
792 }
793 read_merge_msg(&msg);
794 strbuf_stripspace(&msg, 0 < option_edit);
795 if (!msg.len)
796 abort_commit(remoteheads, _("Empty commit message."));
797 strbuf_release(&merge_msg);
798 strbuf_addbuf(&merge_msg, &msg);
799 strbuf_release(&msg);
800}
801static int merge_trivial(struct commit *head, struct commit_list *remoteheads)
803{
804 unsigned char result_tree[20], result_commit[20];
805 struct commit_list *parents, **pptr = &parents;
806 static struct lock_file lock;
807 hold_locked_index(&lock, 1);
809 refresh_cache(REFRESH_QUIET);
810 if (active_cache_changed &&
811 write_locked_index(&the_index, &lock, COMMIT_LOCK))
812 return error(_("Unable to write index."));
813 rollback_lock_file(&lock);
814 write_tree_trivial(result_tree);
816 printf(_("Wonderful.\n"));
817 pptr = commit_list_append(head, pptr);
818 pptr = commit_list_append(remoteheads->item, pptr);
819 prepare_to_commit(remoteheads);
820 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
821 result_commit, NULL, sign_commit))
822 die(_("failed to write commit object"));
823 finish(head, remoteheads, result_commit, "In-index merge");
824 drop_save();
825 return 0;
826}
827static int finish_automerge(struct commit *head,
829 int head_subsumed,
830 struct commit_list *common,
831 struct commit_list *remoteheads,
832 unsigned char *result_tree,
833 const char *wt_strategy)
834{
835 struct commit_list *parents = NULL;
836 struct strbuf buf = STRBUF_INIT;
837 unsigned char result_commit[20];
838 free_commit_list(common);
840 parents = remoteheads;
841 if (!head_subsumed || fast_forward == FF_NO)
842 commit_list_insert(head, &parents);
843 strbuf_addch(&merge_msg, '\n');
844 prepare_to_commit(remoteheads);
845 if (commit_tree(merge_msg.buf, merge_msg.len, result_tree, parents,
846 result_commit, NULL, sign_commit))
847 die(_("failed to write commit object"));
848 strbuf_addf(&buf, "Merge made by the '%s' strategy.", wt_strategy);
849 finish(head, remoteheads, result_commit, buf.buf);
850 strbuf_release(&buf);
851 drop_save();
852 return 0;
853}
854static int suggest_conflicts(void)
856{
857 const char *filename;
858 FILE *fp;
859 struct strbuf msgbuf = STRBUF_INIT;
860 filename = git_path_merge_msg();
862 fp = fopen(filename, "a");
863 if (!fp)
864 die_errno(_("Could not open '%s' for writing"), filename);
865 append_conflicts_hint(&msgbuf);
867 fputs(msgbuf.buf, fp);
868 strbuf_release(&msgbuf);
869 fclose(fp);
870 rerere(allow_rerere_auto);
871 printf(_("Automatic merge failed; "
872 "fix conflicts and then commit the result.\n"));
873 return 1;
874}
875static struct commit *is_old_style_invocation(int argc, const char **argv,
877 const unsigned char *head)
878{
879 struct commit *second_token = NULL;
880 if (argc > 2) {
881 unsigned char second_sha1[20];
882 if (get_sha1(argv[1], second_sha1))
884 return NULL;
885 second_token = lookup_commit_reference_gently(second_sha1, 0);
886 if (!second_token)
887 die(_("'%s' is not a commit"), argv[1]);
888 if (hashcmp(second_token->object.oid.hash, head))
889 return NULL;
890 }
891 return second_token;
892}
893static int evaluate_result(void)
895{
896 int cnt = 0;
897 struct rev_info rev;
898 /* Check how many files differ. */
900 init_revisions(&rev, "");
901 setup_revisions(0, NULL, &rev, NULL);
902 rev.diffopt.output_format |=
903 DIFF_FORMAT_CALLBACK;
904 rev.diffopt.format_callback = count_diff_files;
905 rev.diffopt.format_callback_data = &cnt;
906 run_diff_files(&rev, 0);
907 /*
909 * Check how many unmerged entries are
910 * there.
911 */
912 cnt += count_unmerged_entries();
913 return cnt;
915}
916/*
918 * Pretend as if the user told us to merge with the remote-tracking
919 * branch we have for the upstream of the current branch
920 */
921static int setup_with_upstream(const char ***argv)
922{
923 struct branch *branch = branch_get(NULL);
924 int i;
925 const char **args;
926 if (!branch)
928 die(_("No current branch."));
929 if (!branch->remote_name)
930 die(_("No remote for the current branch."));
931 if (!branch->merge_nr)
932 die(_("No default upstream defined for the current branch."));
933 args = xcalloc(st_add(branch->merge_nr, 1), sizeof(char *));
935 for (i = 0; i < branch->merge_nr; i++) {
936 if (!branch->merge[i]->dst)
937 die(_("No remote-tracking branch for %s from %s"),
938 branch->merge[i]->src, branch->remote_name);
939 args[i] = branch->merge[i]->dst;
940 }
941 args[i] = NULL;
942 *argv = args;
943 return i;
944}
945static void write_merge_state(struct commit_list *remoteheads)
947{
948 struct commit_list *j;
949 struct strbuf buf = STRBUF_INIT;
950 for (j = remoteheads; j; j = j->next) {
952 struct object_id *oid;
953 struct commit *c = j->item;
954 if (c->util && merge_remote_util(c)->obj) {
955 oid = &merge_remote_util(c)->obj->oid;
956 } else {
957 oid = &c->object.oid;
958 }
959 strbuf_addf(&buf, "%s\n", oid_to_hex(oid));
960 }
961 write_file_buf(git_path_merge_head(), buf.buf, buf.len);
962 strbuf_addch(&merge_msg, '\n');
963 write_file_buf(git_path_merge_msg(), merge_msg.buf, merge_msg.len);
964 strbuf_reset(&buf);
966 if (fast_forward == FF_NO)
967 strbuf_addf(&buf, "no-ff");
968 write_file_buf(git_path_merge_mode(), buf.buf, buf.len);
969}
970static int default_edit_option(void)
972{
973 static const char name[] = "GIT_MERGE_AUTOEDIT";
974 const char *e = getenv(name);
975 struct stat st_stdin, st_stdout;
976 if (have_message)
978 /* an explicit -m msg without --[no-]edit */
979 return 0;
980 if (e) {
982 int v = git_config_maybe_bool(name, e);
983 if (v < 0)
984 die(_("Bad value '%s' in environment '%s'"), e, name);
985 return v;
986 }
987 /* Use editor if stdin and stdout are the same and is a tty */
989 return (!fstat(0, &st_stdin) &&
990 !fstat(1, &st_stdout) &&
991 isatty(0) && isatty(1) &&
992 st_stdin.st_dev == st_stdout.st_dev &&
993 st_stdin.st_ino == st_stdout.st_ino &&
994 st_stdin.st_mode == st_stdout.st_mode);
995}
996static struct commit_list *reduce_parents(struct commit *head_commit,
998 int *head_subsumed,
999 struct commit_list *remoteheads)
1000{
1001 struct commit_list *parents, **remotes;
1002 /*
1004 * Is the current HEAD reachable from another commit being
1005 * merged? If so we do not want to record it as a parent of
1006 * the resulting merge, unless --no-ff is given. We will flip
1007 * this variable to 0 when we find HEAD among the independent
1008 * tips being merged.
1009 */
1010 *head_subsumed = 1;
1011 /* Find what parents to record by checking independent ones. */
1013 parents = reduce_heads(remoteheads);
1014 remoteheads = NULL;
1016 remotes = &remoteheads;
1017 while (parents) {
1018 struct commit *commit = pop_commit(&parents);
1019 if (commit == head_commit)
1020 *head_subsumed = 0;
1021 else
1022 remotes = &commit_list_insert(commit, remotes)->next;
1023 }
1024 return remoteheads;
1025}
1026static void prepare_merge_message(struct strbuf *merge_names, struct strbuf *merge_msg)
1028{
1029 struct fmt_merge_msg_opts opts;
1030 memset(&opts, 0, sizeof(opts));
1032 opts.add_title = !have_message;
1033 opts.shortlog_len = shortlog_len;
1034 opts.credit_people = (0 < option_edit);
1035 fmt_merge_msg(merge_names, merge_msg, &opts);
1037 if (merge_msg->len)
1038 strbuf_setlen(merge_msg, merge_msg->len - 1);
1039}
1040static void handle_fetch_head(struct commit_list **remotes, struct strbuf *merge_names)
1042{
1043 const char *filename;
1044 int fd, pos, npos;
1045 struct strbuf fetch_head_file = STRBUF_INIT;
1046 if (!merge_names)
1048 merge_names = &fetch_head_file;
1049 filename = git_path_fetch_head();
1051 fd = open(filename, O_RDONLY);
1052 if (fd < 0)
1053 die_errno(_("could not open '%s' for reading"), filename);
1054 if (strbuf_read(merge_names, fd, 0) < 0)
1056 die_errno(_("could not read '%s'"), filename);
1057 if (close(fd) < 0)
1058 die_errno(_("could not close '%s'"), filename);
1059 for (pos = 0; pos < merge_names->len; pos = npos) {
1061 unsigned char sha1[20];
1062 char *ptr;
1063 struct commit *commit;
1064 ptr = strchr(merge_names->buf + pos, '\n');
1066 if (ptr)
1067 npos = ptr - merge_names->buf + 1;
1068 else
1069 npos = merge_names->len;
1070 if (npos - pos < 40 + 2 ||
1072 get_sha1_hex(merge_names->buf + pos, sha1))
1073 commit = NULL; /* bad */
1074 else if (memcmp(merge_names->buf + pos + 40, "\t\t", 2))
1075 continue; /* not-for-merge */
1076 else {
1077 char saved = merge_names->buf[pos + 40];
1078 merge_names->buf[pos + 40] = '\0';
1079 commit = get_merge_parent(merge_names->buf + pos);
1080 merge_names->buf[pos + 40] = saved;
1081 }
1082 if (!commit) {
1083 if (ptr)
1084 *ptr = '\0';
1085 die(_("not something we can merge in %s: %s"),
1086 filename, merge_names->buf + pos);
1087 }
1088 remotes = &commit_list_insert(commit, remotes)->next;
1089 }
1090 if (merge_names == &fetch_head_file)
1092 strbuf_release(&fetch_head_file);
1093}
1094static struct commit_list *collect_parents(struct commit *head_commit,
1096 int *head_subsumed,
1097 int argc, const char **argv,
1098 struct strbuf *merge_msg)
1099{
1100 int i;
1101 struct commit_list *remoteheads = NULL;
1102 struct commit_list **remotes = &remoteheads;
1103 struct strbuf merge_names = STRBUF_INIT, *autogen = NULL;
1104 if (merge_msg && (!have_message || shortlog_len))
1106 autogen = &merge_names;
1107 if (head_commit)
1109 remotes = &commit_list_insert(head_commit, remotes)->next;
1110 if (argc == 1 && !strcmp(argv[0], "FETCH_HEAD")) {
1112 handle_fetch_head(remotes, autogen);
1113 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1114 } else {
1115 for (i = 0; i < argc; i++) {
1116 struct commit *commit = get_merge_parent(argv[i]);
1117 if (!commit)
1118 help_unknown_ref(argv[i], "merge",
1119 _("not something we can merge"));
1120 remotes = &commit_list_insert(commit, remotes)->next;
1121 }
1122 remoteheads = reduce_parents(head_commit, head_subsumed, remoteheads);
1123 if (autogen) {
1124 struct commit_list *p;
1125 for (p = remoteheads; p; p = p->next)
1126 merge_name(merge_remote_util(p->item)->name, autogen);
1127 }
1128 }
1129 if (autogen) {
1131 prepare_merge_message(autogen, merge_msg);
1132 strbuf_release(autogen);
1133 }
1134 return remoteheads;
1136}
1137int cmd_merge(int argc, const char **argv, const char *prefix)
1139{
1140 unsigned char result_tree[20];
1141 unsigned char stash[20];
1142 unsigned char head_sha1[20];
1143 struct commit *head_commit;
1144 struct strbuf buf = STRBUF_INIT;
1145 const char *head_arg;
1146 int i, ret = 0, head_subsumed;
1147 int best_cnt = -1, merge_was_ok = 0, automerge_was_ok = 0;
1148 struct commit_list *common = NULL;
1149 const char *best_strategy = NULL, *wt_strategy = NULL;
1150 struct commit_list *remoteheads, *p;
1151 void *branch_to_free;
1152 if (argc == 2 && !strcmp(argv[1], "-h"))
1154 usage_with_options(builtin_merge_usage, builtin_merge_options);
1155 /*
1157 * Check if we are _not_ on a detached HEAD, i.e. if there is a
1158 * current branch.
1159 */
1160 branch = branch_to_free = resolve_refdup("HEAD", 0, head_sha1, NULL);
1161 if (branch && starts_with(branch, "refs/heads/"))
1162 branch += 11;
1163 if (!branch || is_null_sha1(head_sha1))
1164 head_commit = NULL;
1165 else
1166 head_commit = lookup_commit_or_die(head_sha1, "HEAD");
1167 init_diff_ui_defaults();
1169 git_config(git_merge_config, NULL);
1170 if (branch_mergeoptions)
1172 parse_branch_merge_options(branch_mergeoptions);
1173 argc = parse_options(argc, argv, prefix, builtin_merge_options,
1174 builtin_merge_usage, 0);
1175 if (shortlog_len < 0)
1176 shortlog_len = (merge_log_config > 0) ? merge_log_config : 0;
1177 if (verbosity < 0 && show_progress == -1)
1179 show_progress = 0;
1180 if (abort_current_merge) {
1182 int nargc = 2;
1183 const char *nargv[] = {"reset", "--merge", NULL};
1184 if (!file_exists(git_path_merge_head()))
1186 die(_("There is no merge to abort (MERGE_HEAD missing)."));
1187 /* Invoke 'git reset --merge' */
1189 ret = cmd_reset(nargc, nargv, prefix);
1190 goto done;
1191 }
1192 if (read_cache_unmerged())
1194 die_resolve_conflict("merge");
1195 if (file_exists(git_path_merge_head())) {
1197 /*
1198 * There is no unmerged entry, don't advise 'git
1199 * add/rm <file>', just 'git commit'.
1200 */
1201 if (advice_resolve_conflict)
1202 die(_("You have not concluded your merge (MERGE_HEAD exists).\n"
1203 "Please, commit your changes before you merge."));
1204 else
1205 die(_("You have not concluded your merge (MERGE_HEAD exists)."));
1206 }
1207 if (file_exists(git_path_cherry_pick_head())) {
1208 if (advice_resolve_conflict)
1209 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists).\n"
1210 "Please, commit your changes before you merge."));
1211 else
1212 die(_("You have not concluded your cherry-pick (CHERRY_PICK_HEAD exists)."));
1213 }
1214 resolve_undo_clear();
1215 if (verbosity < 0)
1217 show_diffstat = 0;
1218 if (squash) {
1220 if (fast_forward == FF_NO)
1221 die(_("You cannot combine --squash with --no-ff."));
1222 option_commit = 0;
1223 }
1224 if (!argc) {
1226 if (default_to_upstream)
1227 argc = setup_with_upstream(&argv);
1228 else
1229 die(_("No commit specified and merge.defaultToUpstream not set."));
1230 } else if (argc == 1 && !strcmp(argv[0], "-")) {
1231 argv[0] = "@{-1}";
1232 }
1233 if (!argc)
1235 usage_with_options(builtin_merge_usage,
1236 builtin_merge_options);
1237 if (!head_commit) {
1239 /*
1240 * If the merged head is a valid one there is no reason
1241 * to forbid "git merge" into a branch yet to be born.
1242 * We do the same for "git pull".
1243 */
1244 unsigned char *remote_head_sha1;
1245 if (squash)
1246 die(_("Squash commit into empty head not supported yet"));
1247 if (fast_forward == FF_NO)
1248 die(_("Non-fast-forward commit does not make sense into "
1249 "an empty head"));
1250 remoteheads = collect_parents(head_commit, &head_subsumed,
1251 argc, argv, NULL);
1252 if (!remoteheads)
1253 die(_("%s - not something we can merge"), argv[0]);
1254 if (remoteheads->next)
1255 die(_("Can merge only exactly one commit into empty head"));
1256 remote_head_sha1 = remoteheads->item->object.oid.hash;
1257 read_empty(remote_head_sha1, 0);
1258 update_ref("initial pull", "HEAD", remote_head_sha1,
1259 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1260 goto done;
1261 }
1262 /*
1264 * This could be traditional "merge <msg> HEAD <commit>..." and
1265 * the way we can tell it is to see if the second token is HEAD,
1266 * but some people might have misused the interface and used a
1267 * commit-ish that is the same as HEAD there instead.
1268 * Traditional format never would have "-m" so it is an
1269 * additional safety measure to check for it.
1270 */
1271 if (!have_message &&
1272 is_old_style_invocation(argc, argv, head_commit->object.oid.hash)) {
1273 warning("old-style 'git merge <msg> HEAD <commit>' is deprecated.");
1274 strbuf_addstr(&merge_msg, argv[0]);
1275 head_arg = argv[1];
1276 argv += 2;
1277 argc -= 2;
1278 remoteheads = collect_parents(head_commit, &head_subsumed,
1279 argc, argv, NULL);
1280 } else {
1281 /* We are invoked directly as the first-class UI. */
1282 head_arg = "HEAD";
1283 /*
1285 * All the rest are the commits being merged; prepare
1286 * the standard merge summary message to be appended
1287 * to the given message.
1288 */
1289 remoteheads = collect_parents(head_commit, &head_subsumed,
1290 argc, argv, &merge_msg);
1291 }
1292 if (!head_commit || !argc)
1294 usage_with_options(builtin_merge_usage,
1295 builtin_merge_options);
1296 if (verify_signatures) {
1298 for (p = remoteheads; p; p = p->next) {
1299 struct commit *commit = p->item;
1300 char hex[GIT_SHA1_HEXSZ + 1];
1301 struct signature_check signature_check;
1302 memset(&signature_check, 0, sizeof(signature_check));
1303 check_commit_signature(commit, &signature_check);
1305 find_unique_abbrev_r(hex, commit->object.oid.hash, DEFAULT_ABBREV);
1307 switch (signature_check.result) {
1308 case 'G':
1309 break;
1310 case 'U':
1311 die(_("Commit %s has an untrusted GPG signature, "
1312 "allegedly by %s."), hex, signature_check.signer);
1313 case 'B':
1314 die(_("Commit %s has a bad GPG signature "
1315 "allegedly by %s."), hex, signature_check.signer);
1316 default: /* 'N' */
1317 die(_("Commit %s does not have a GPG signature."), hex);
1318 }
1319 if (verbosity >= 0 && signature_check.result == 'G')
1320 printf(_("Commit %s has a good GPG signature by %s\n"),
1321 hex, signature_check.signer);
1322 signature_check_clear(&signature_check);
1324 }
1325 }
1326 strbuf_addstr(&buf, "merge");
1328 for (p = remoteheads; p; p = p->next)
1329 strbuf_addf(&buf, " %s", merge_remote_util(p->item)->name);
1330 setenv("GIT_REFLOG_ACTION", buf.buf, 0);
1331 strbuf_reset(&buf);
1332 for (p = remoteheads; p; p = p->next) {
1334 struct commit *commit = p->item;
1335 strbuf_addf(&buf, "GITHEAD_%s",
1336 oid_to_hex(&commit->object.oid));
1337 setenv(buf.buf, merge_remote_util(commit)->name, 1);
1338 strbuf_reset(&buf);
1339 if (fast_forward != FF_ONLY &&
1340 merge_remote_util(commit) &&
1341 merge_remote_util(commit)->obj &&
1342 merge_remote_util(commit)->obj->type == OBJ_TAG)
1343 fast_forward = FF_NO;
1344 }
1345 if (option_edit < 0)
1347 option_edit = default_edit_option();
1348 if (!use_strategies) {
1350 if (!remoteheads)
1351 ; /* already up-to-date */
1352 else if (!remoteheads->next)
1353 add_strategies(pull_twohead, DEFAULT_TWOHEAD);
1354 else
1355 add_strategies(pull_octopus, DEFAULT_OCTOPUS);
1356 }
1357 for (i = 0; i < use_strategies_nr; i++) {
1359 if (use_strategies[i]->attr & NO_FAST_FORWARD)
1360 fast_forward = FF_NO;
1361 if (use_strategies[i]->attr & NO_TRIVIAL)
1362 allow_trivial = 0;
1363 }
1364 if (!remoteheads)
1366 ; /* already up-to-date */
1367 else if (!remoteheads->next)
1368 common = get_merge_bases(head_commit, remoteheads->item);
1369 else {
1370 struct commit_list *list = remoteheads;
1371 commit_list_insert(head_commit, &list);
1372 common = get_octopus_merge_bases(list);
1373 free(list);
1374 }
1375 update_ref("updating ORIG_HEAD", "ORIG_HEAD", head_commit->object.oid.hash,
1377 NULL, 0, UPDATE_REFS_DIE_ON_ERR);
1378 if (remoteheads && !common) {
1380 /* No common ancestors found. */
1381 if (!allow_unrelated_histories)
1382 die(_("refusing to merge unrelated histories"));
1383 /* otherwise, we need a real merge. */
1384 } else if (!remoteheads ||
1385 (!remoteheads->next && !common->next &&
1386 common->item == remoteheads->item)) {
1387 /*
1388 * If head can reach all the merge then we are up to date.
1389 * but first the most common case of merging one remote.
1390 */
1391 finish_up_to_date(_("Already up-to-date."));
1392 goto done;
1393 } else if (fast_forward != FF_NO && !remoteheads->next &&
1394 !common->next &&
1395 !oidcmp(&common->item->object.oid, &head_commit->object.oid)) {
1396 /* Again the most common case of merging one remote. */
1397 struct strbuf msg = STRBUF_INIT;
1398 struct commit *commit;
1399 if (verbosity >= 0) {
1401 char from[GIT_SHA1_HEXSZ + 1], to[GIT_SHA1_HEXSZ + 1];
1402 find_unique_abbrev_r(from, head_commit->object.oid.hash,
1403 DEFAULT_ABBREV);
1404 find_unique_abbrev_r(to, remoteheads->item->object.oid.hash,
1405 DEFAULT_ABBREV);
1406 printf(_("Updating %s..%s\n"), from, to);
1407 }
1408 strbuf_addstr(&msg, "Fast-forward");
1409 if (have_message)
1410 strbuf_addstr(&msg,
1411 " (no commit created; -m option ignored)");
1412 commit = remoteheads->item;
1413 if (!commit) {
1414 ret = 1;
1415 goto done;
1416 }
1417 if (checkout_fast_forward(head_commit->object.oid.hash,
1419 commit->object.oid.hash,
1420 overwrite_ignore)) {
1421 ret = 1;
1422 goto done;
1423 }
1424 finish(head_commit, remoteheads, commit->object.oid.hash, msg.buf);
1426 drop_save();
1427 goto done;
1428 } else if (!remoteheads->next && common->next)
1429 ;
1430 /*
1431 * We are not doing octopus and not fast-forward. Need
1432 * a real merge.
1433 */
1434 else if (!remoteheads->next && !common->next && option_commit) {
1435 /*
1436 * We are not doing octopus, not fast-forward, and have
1437 * only one common.
1438 */
1439 refresh_cache(REFRESH_QUIET);
1440 if (allow_trivial && fast_forward != FF_ONLY) {
1441 /* See if it is really trivial. */
1442 git_committer_info(IDENT_STRICT);
1443 printf(_("Trying really trivial in-index merge...\n"));
1444 if (!read_tree_trivial(common->item->object.oid.hash,
1445 head_commit->object.oid.hash,
1446 remoteheads->item->object.oid.hash)) {
1447 ret = merge_trivial(head_commit, remoteheads);
1448 goto done;
1449 }
1450 printf(_("Nope.\n"));
1451 }
1452 } else {
1453 /*
1454 * An octopus. If we can reach all the remote we are up
1455 * to date.
1456 */
1457 int up_to_date = 1;
1458 struct commit_list *j;
1459 for (j = remoteheads; j; j = j->next) {
1461 struct commit_list *common_one;
1462 /*
1464 * Here we *have* to calculate the individual
1465 * merge_bases again, otherwise "git merge HEAD^
1466 * HEAD^^" would be missed.
1467 */
1468 common_one = get_merge_bases(head_commit, j->item);
1469 if (oidcmp(&common_one->item->object.oid, &j->item->object.oid)) {
1470 up_to_date = 0;
1471 break;
1472 }
1473 }
1474 if (up_to_date) {
1475 finish_up_to_date(_("Already up-to-date. Yeeah!"));
1476 goto done;
1477 }
1478 }
1479 if (fast_forward == FF_ONLY)
1481 die(_("Not possible to fast-forward, aborting."));
1482 /* We are going to make a new commit. */
1484 git_committer_info(IDENT_STRICT);
1485 /*
1487 * At this point, we need a real merge. No matter what strategy
1488 * we use, it would operate on the index, possibly affecting the
1489 * working tree, and when resolved cleanly, have the desired
1490 * tree in the index -- this means that the index must be in
1491 * sync with the head commit. The strategies are responsible
1492 * to ensure this.
1493 */
1494 if (use_strategies_nr == 1 ||
1495 /*
1496 * Stash away the local changes so that we can try more than one.
1497 */
1498 save_state(stash))
1499 hashclr(stash);
1500 for (i = 0; i < use_strategies_nr; i++) {
1502 int ret;
1503 if (i) {
1504 printf(_("Rewinding the tree to pristine...\n"));
1505 restore_state(head_commit->object.oid.hash, stash);
1506 }
1507 if (use_strategies_nr != 1)
1508 printf(_("Trying merge strategy %s...\n"),
1509 use_strategies[i]->name);
1510 /*
1511 * Remember which strategy left the state in the working
1512 * tree.
1513 */
1514 wt_strategy = use_strategies[i]->name;
1515 ret = try_merge_strategy(use_strategies[i]->name,
1517 common, remoteheads,
1518 head_commit, head_arg);
1519 if (!option_commit && !ret) {
1520 merge_was_ok = 1;
1521 /*
1522 * This is necessary here just to avoid writing
1523 * the tree, but later we will *not* exit with
1524 * status code 1 because merge_was_ok is set.
1525 */
1526 ret = 1;
1527 }
1528 if (ret) {
1530 /*
1531 * The backend exits with 1 when conflicts are
1532 * left to be resolved, with 2 when it does not
1533 * handle the given merge at all.
1534 */
1535 if (ret == 1) {
1536 int cnt = evaluate_result();
1537 if (best_cnt <= 0 || cnt <= best_cnt) {
1539 best_strategy = use_strategies[i]->name;
1540 best_cnt = cnt;
1541 }
1542 }
1543 if (merge_was_ok)
1544 break;
1545 else
1546 continue;
1547 }
1548 /* Automerge succeeded. */
1550 write_tree_trivial(result_tree);
1551 automerge_was_ok = 1;
1552 break;
1553 }
1554 /*
1556 * If we have a resulting tree, that means the strategy module
1557 * auto resolved the merge cleanly.
1558 */
1559 if (automerge_was_ok) {
1560 ret = finish_automerge(head_commit, head_subsumed,
1561 common, remoteheads,
1562 result_tree, wt_strategy);
1563 goto done;
1564 }
1565 /*
1567 * Pick the result from the best strategy and have the user fix
1568 * it up.
1569 */
1570 if (!best_strategy) {
1571 restore_state(head_commit->object.oid.hash, stash);
1572 if (use_strategies_nr > 1)
1573 fprintf(stderr,
1574 _("No merge strategy handled the merge.\n"));
1575 else
1576 fprintf(stderr, _("Merge with strategy %s failed.\n"),
1577 use_strategies[0]->name);
1578 ret = 2;
1579 goto done;
1580 } else if (best_strategy == wt_strategy)
1581 ; /* We already have its result in the working tree. */
1582 else {
1583 printf(_("Rewinding the tree to pristine...\n"));
1584 restore_state(head_commit->object.oid.hash, stash);
1585 printf(_("Using the %s to prepare resolving by hand.\n"),
1586 best_strategy);
1587 try_merge_strategy(best_strategy, common, remoteheads,
1588 head_commit, head_arg);
1589 }
1590 if (squash)
1592 finish(head_commit, remoteheads, NULL, NULL);
1593 else
1594 write_merge_state(remoteheads);
1595 if (merge_was_ok)
1597 fprintf(stderr, _("Automatic merge went well; "
1598 "stopped before committing as requested\n"));
1599 else
1600 ret = suggest_conflicts();
1601done:
1603 free(branch_to_free);
1604 return ret;
1605}